The present invention relates generally to engine oil sensors.
Automatically monitoring the quality of oil in an engine alerts owners or operators of the engine in a timely fashion when maintenance should be performed as dictated by the actual condition of the oil. Performing maintenance when it is actually required is preferred over following a predetermined, one-size-fits-all schedule that might be too long or too short for any given vehicle, depending on the way the vehicle is driven. If too long a period elapses between maintenance, a vehicle can be damaged. On the other hand, conducting maintenance when it is not needed is wasteful both in terms of labor and in terms of natural resources. For example, if a vehicle doesn""t require an oil change but nevertheless receives one, oil is in effect wasted.
Accordingly, oil condition sensors, having a generally cylindrical shape, have been provided for measuring various parameters of lubricating oil, and to generate warning signals when maintenance is due as indicated by the condition of the oil. Among the parameters that are typically measured are oil temperature, contamination, and degradation. In a light vehicle, these sensors are usually mounted in the oil pan beneath the engine. The sensitivity of these sensors relies heavily on the surface area of the sensor. Thus, as the surface area increases, the signal strength increases.
The present invention recognizes that in order to increase the surface area, either the length of the sensor or the diameter of the sensor is increased. Because of sensor size considerations, it is often the length of the oil condition sensor that is increased instead of the diameter of the sensor. Unfortunately, in an oil pan, the length of the sensor is constrained by the depth of the pan. As such, the present invention understands that in deep oil pans the length of the sensor can be increased without problem, but in shallow oil pans increasing the length of the sensor can be problematic.
The present invention has recognized these prior art drawbacks, and has provided the below-disclosed solutions to one or more of the prior art deficiencies.
A flexible circuit film engine oil sensor includes a core structure and a flexible circuit film that is wrapped around the core structure to form a spiral fluid chamber that is filled with oil. In a preferred embodiment, the sensor includes a flexible border that surrounds the flexible circuit film. Moreover, the sensor preferably includes a weld flap and a core support flap. The weld flap and the core support flap are attached to opposite ends of the flexible border.
In a preferred embodiment, the flexible circuit film includes an oil condition sensing electrode surface, a resistive temperature device, and a common electrode surface. Preferably, the sensor also includes a plurality of ribs that are affixed to a surface of the sensor.
In one aspect of the present invention, the flexible circuit film also includes an oil level sensing electrode surface. Moreover, this aspect of the present invention includes a plurality of spacers that are aligned with the ribs on an opposite surface of the sensor. When the sensor is wrapped around a core structure, the spacers align with the ribs. In this aspect of the present invention, the core structure is a solid rod and the sensor is installed in an oil pan to monitor condition, temperature, and level of oil therein.
In another aspect of the present invention, the sensor includes a plurality of holes that are formed between the ribs. The holes allow oil to flow radially through the sensor. In this aspect of the present invention, the core structure is a hollow, inlet tube. The inlet tube forms an inlet port that communicates with the spiral fluid chamber formed by the sensor. Moreover, the sensor is installed along a fluid line of a lubrication system to monitor condition and temperature of oil therein.
In yet another aspect of the present invention, a vehicle oil lubricating system includes an engine, an oil pan, and an oil sensor. The sensor includes a core structure and a flexible circuit film that is wrapped around the core structure to form a spiral fluid chamber. The spiral fluid chamber is filled with oil which is monitored therein.